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200-5 




ABC OF 

SPRAY PAINTING 
EQUIPMENT 

Answers \o the mosf common Questions pertaining 
to Spray Guns, Cups, Tanks, Transformers, Air Com- 
pressors, and other items of Spray Painting Equipment 



Price: Twenty-Five Cents 



THE DeVILBISS COMPANY 

TOLEDO, OHIO 



Copvrioht 1940, The DeVllbis* Company, Toledo, Ohio 



-is-. 



FOREWORD 

This booklet contains practically all of the common questions and an- 
.swers pertaining to the operation and use, care, and adjustment of Spray 
Painting Equipment. It is in answer to many requests for a simple book 
let which would provide the ground work for a general understanding of 
all the basic principles involved. The questions selected were chosen from 
hundreds which have been repeated time and again at the DeVilbiss Train- 
ing School * and at numerous clinics. While the questions included are 
those asked by the layman, whose knowledge of this type of equipment 
may be rather limited, an earnest attempt has been made to introduce and 
clarify a good many of those questions which are frequently asked by thost* 
who are familiar with spray equipment. 



• The DeVilbiss Training School is conducted at the main plant of The DeVilbiss 
Company in Toledo. Ohio. 



CONTENTS 



Page 



i ^i i I SPRAY GUNS 

Definition— Types— Uses— Principal Parts — Features— Operation — Care 
•nd Cleaning— Lubrication— Troubles and Remedies -Accessories. 

P*'^T n MATERIAL CONTAINERS 

I )efmition— Types— Uses— Principal Parts— Features-ConstrucUon- Ac - 



^,^l III HOSE and CONNECTION 
Hose— Types— Construction— Sj . 



Connections— Types— Assembl y 



PART IV AIR TRANSFORMERS and CONDENSERS 

'rtA—lnstallation— Caie and Cleaning— 



20 



PART V AIR COMPRESSING OUTFITS 

T- ' - •• 



22 



—Troubles and ReiTi< 

INDEX 



w/iri i.iitjj n .,M<ji> <_••;«- 



31 



Part I. PAINT SPRAY GUN 

1. WTiat is a Paint Spray Gun? 

A Paint Spray Gun is a mechanical means of bringing 
air and paint together, atomizing or breaking up paint 
stream into a spray, and ejecting it for the purpose of 
applying a coating to some object or surface to preserve 
or beautify it. 

2. What types of Spray Guns are there? 

Spray Guns are of Attached Container or Separate Con- 
tainer Type (See Figs. 1 & 2). These two types can be 
further divided into Bleeder and Non-Bleeder, External 
and Internal Mix, and Pressure, Gravity or Suction Feed 
Guns, etc. 

3. What is a Bleeder Type Gun? 

A Gun that "bleeds" air continually (Fig. 3). By "bleeds" 
is meant an intentional leakage from some part of the 
gun. This prevents air pressure building up in hose and, 
therefore, is used with small air compressing outfits 
having no pressure controlling device such as Unloader 
or Pressure Switch. In this type of gun, trigger controls 
flow of fluid only. 

4. What is a Non-Bleeder Type Gun? 

A Gun equipped with an air valve which shuts off the 
air when the trigger is released (Fig. 4). In this type of 
gun, trigger controls both air and fluid. It is used with 
compressing outfits having a pressure controlling device. 

5. What is an External Mix Type Gun? 

A Gun which mixes air and material outside the Air 
Cap (Fig. 5). 

6. What b an Internal Mix Type Gun? 

A Gun which mixes air and material inside the Air Cap 
(Fig. 6). 

7. What is a Suction Feed Type Gun? 

A Gun whose Air Cap (Fig. 7) is designed to create a 
vacuum (Fluid Tip protrudes above Air Cap) and thus 
draw the material from the container. This type gun is 
usually limited to quart size containers or smaller. 

8. What is a Pressure Feed Type Spray Gun? 

A Gun whose Air Cap (Fig. 8) is not necessarily de- 
signed to create a vacuum (Fluid Tip is flush with Air 
Cap). On this type, air pressure is required to force 
material from container to gun. 

9. What is a Gravity Feed Type Spray Gun? 

A Gun that can be fed from an overhead container by 
force of gravity. The Air Cap for this should be of the 
Suction Feed type (Fig. 7). 

[ 3 ] 




ms£ o» 

CUP AT r ACMES 
HERE 



SEPA RA TE CON TA INER 
TYPE 




ATTA CM ED CON TA INER 
TYPE 





BLEEDER TYPE 



AIR VALVE 
SHUTS OFF 
Am WHEN TRICCER 
IS AELEASEO 



NON- BLEEDER TYPE 




Ci 



EXTERNAL MIX AIR CAP 




INTERNAL MIX AIR CAP 



d)» cufmiNTS - 

CR£AT£ A yACi 




SUCr/O/V OR GRAVITY 
FEED CAP 



FLUID TIP IS 

FLUSH turn 

Alfi CAP - 



1 



PRESSURE FEED CAP 





FLUID 
NEEDLC 
AJUSTMCNT 
FIG.IO 



¥ALVE 

cuN Boor 



10. What are the principal parts of a Spray Gun? 

The principal parts are the Gun Body Assembly (Fig. 
9) and Removable Spray Head Assembly. 

11. What are the principal parts of the Gun Body Assembly? 

The Spreader Adjustment Valve, Air Valve, Fluid Needle 
Adjustment, Spray head Locking Bolt, and Gun Body 
(Fig. 10). 



12. What is the Spreader Adjustment Valve? 

A valve with graduated dial for controlling the air to 
the spreader horn holes of the Air Cap (Fig. 10). By 
means of this valve adjustments from round spray to 
various width flat patterns can be made (Fig. 11). Gradu- 
ated adjustment shown on dial permits quick return to 
desired spray pattern. 



13. What is the Air Valve? 

A Valve in the Gun Body which controls the air (Fig. 10). 
It is opened and closed by the pull and release of the 
trigger. 



14. What is the Fluid Needle Adjustment? 

This valve controls the movement of the Fluid Needle 
which allows more or less material through the nozzle 
(Fig. 10). 



SPRAY PATTERNS AT 
DIAL SETT IN 



I 



II 

DIAL AT S ^ ^^ 



D/AL AT 10 



15. What is a Sprayhead Lock- 
ing Bolt? 

This is the bolt which locks 
the Removable Spray Head 
and Gun Body together (Fig. 
10). 

16. What Is a Removable Spray 
Head and what are its ad- 
vantages? 

A feature which allows the 

Spray Head (an assembly 

consisting of the Air Cap, Fluid Tip. Fluid Needle and Spray Head Barrel) to be 

quickly removed as a imit from the Spray Gun Body (Fig. 9). Its advantages are: 

1. Quick change from one material or color to another. One Spray Gun Body with 
several heads will answer purpose of what otherwise may require several guns. 

2. Ease of cleaning. 

3. In case of damage to front of gun, new gun body is not required. 

4. An extra Spray Head can be substituted for one being repaired or cleaned. 

[ 4 1 




HOLD TRICCEH 

BACK AMQ LOaSSM 

LOCHtNC BOLT _ _ _ ^^^^^ s^l>Ar H£A0 

METHOD OF REMOVING SPRAVHEAD FROM GUN BODY 




CONVENTIONAL AIR 

CAP 



THȣE HOL E 




17. How is the Spray Head removed? 

Hold gun in left hand (Fig. 12) and hold trigger all the 
way back. Loosen Locking Bolt with small wrench pro- 
vided. Push trigger forward as far as possible with back 
of fingers. Pull Spray Head forward. 
To replace, push trigger forward and insert Spray Head. 
Hold trigger back and tighten Locking Bolt. 

18. Can more than one Spray Head be provided? 

Yes. A wide variety of Spray Heads incorporating many 
air cap and nozzle combinations for practically all types 
of materials and for special applications and decorative 
effects are available. Examples of these are: Decorator's 
Head, Plastics Head, Asphalt Head, etc. 

19. What are the principal parts of the Spray Head? 

The Air Cap, Fluid Tip, Fluid Needle, Baffle and Spray 
Head Barrel (Fig. 13). 

20. What is the Air Cap? 

That part at the front of the gun (Fig. 13) which directs 

the air into the material stream to break up (atomize) the material and form 

it into a suitable spray pattern. 

21. What Types of Air Caps are there? 

All caps can be divided into External Mix or Internal Mix Types (Figs. 5 & 6) . In 
the Internal Mix Cap air and material mix inside and are ejected through a slot; with 
the External Mix Cap air is ejected through two spreader horns, through a center 
orifice and sometimes auxiliary orifices. These caps can be divided into two groups: 

1. Conventional — with 3 orifices: a center orifice and one in each horn (Fig. 14). 

2. Multiple Jet — with 5, 7 or 9 orifices: a center orifice, one in each horn, plus 
Twin Jets and Auxiliary Jets (Fig. 15). 




MULTIPLE JET AIR CAP 



■TWIM J£T 
HORN HOLE 




22. What are the advantages of a Multiple Jet Cap? 

Advantages of these caps are as follows: 

1. Better atomization for the more viscous materials such as sjmthetics, heavy 
bodied lacquers, etc. 

[ 5 ] 



STANOARD NOZZLE SIZES. 




. . . SHOWING COMPARATIVE SIZES OF FLUID TIPS 



2. Elimination of "split spray" pattern due to high pressure required to atomize 
more viscous materials. 

3. Greater uniformity in pattern due to better equalization of air volume and pres- 
sure from cap. 

23. How should an Air Cap be selected? 

On the following factors: 

1. Volume of air (in cubic feet per minute) and pressure (in pounds per square 
inch) available. 

2. Material Feed System to be used, viz., pressure, suction, or gravity feed. 

3. Type of material and volume to be sprayed. 

4. Nozzle size of Fluid Tip to be used. Most air caps work best with certain nozzle 
sizes. For example, some air caps work best over F or FX tips, but can be used 
with certain materials over FF or E tips. 

5. Size and nature of object or surface to be sprayed. 

Many or large orifices increase ability to atomize heavy or viscous materials, but 
this also increases amount of air required. Fewer or smaller orifices require less 
air, but result in decreased spraying speed and material atomization. 
The higher the specific gravity or viscosity of the material, the more difficult it 
is to atomize. Also, the more rapid the flow, the more air velocity required to 
maintain the proper relation between air and fluid pressure. 



FIG 17 


E 


H02ZL £ 


SUE 


1 








FLUID 


NEEDLE 





FLUID 


c 


A.. 


^ koiZLE Size 

FIG IS 


TIP 






W 



24. What is the Fluid Tip? 

That part at the front end of the gun (Fig. 13) which meters and directs the ma- 
terial into the air streams. It provides a self-aligning, concentric (Ball and Cone) 
seat for the Air Cap, and equalizes the air leaving center orifice of the cap. 

25. WTiat are the standard nozzle sizes? 

Standard sizes are as follows: A-C-D-E-FF-FX-F-G. (See Fig. 16.) 
Note: "Nozzle" by usage refers to the opening in Fluid Tip. 

26. How are nozzle sizes identified? 

By a letter stamped on collar of the Needle (Fig. 17) and on the outer edge of 
the Fluid Tip (Fig. 18). 

27. Which nozzle sizes are most common? 

Sizes E-FF-FX-F (Fig. 16) are most generally used. 

28. How should the Fluid Tip be selected? 

In selecting the proper fluid tip, consideration should be given to several important 



factors: 



[ 6 1 



1. Heavy, coarse or fibrous materials require large nozzle 
sizes (Fig. 16), to permit passage of the material and 
prevent clogging. 

Example: Plastic Paints — CS Nozzle (Pressure Feed 
only). 

2. Viscous materials requiring high atomizing pressures 
are handled better through the small nozzle sizes 
which assure more complete atomization. 
Example: Synthetic Enamels — 

FF Nozzle — For high atomization — Suction Feed. 
F or FX Nozzle — For high atomization — Pressure Feed. 

3. Very thin materials that sag readily are applied at low 
atomizing pressures with small nozzle sizes to prevent 
excessive material application. 

Example: Stains— FF Nozzle — Suction Feed. 
F Nozzle — Pressure Feed. 

4. Abrasive or corrosive materials must be handled with 
tips made of wear-resistant or non-corrosive metals. 
Exam.ple: Wood Bleaches as used in furniture manu- 
facture and Metal Cleaners require non-cor- 
rosive tips. Porcelain Enamel requires non- 
abrasive tips. 

5. Type of material feed to be used. The nozzle size 
sometimes recommended for Suction Feed will not be 
satisfactory for Pressure Feed. 

Example: Lacquer — E Nozzle — Suction Feed. 

F or FX Nozzle— Pressure^ Feed. 

29. Of what metals are Fluid Tips made? 

Tips are made of the following metals: 

1. Hardened Steel for ordinary materials not corrosive 
or exceedingly abrasive. 

2. Nitralloy for abrasive, but not corrosive materials. 

3. Stainless Steel for corrosive materials. 

4. Specially hardened alloy inserts for extremely abrasive 
materials. 

30. What is the "Ball and Cone" principle? 

A feature *(Fig. 19) which assures perfect alignment be- 
tween the Air Cap and Fluid Tip. A precision machined 
conical surface on the tip provides a seat for the precision 
machined ball segm.ent of the cap. 

31. How should the paint be prepared for spraying? 

Stir contents thoroughly. Mix according to manufac- 
turer's directions. Use paint for spraying same as you 
would for brushing. If it contains any lumps or skins, 
strain through screen (Fig. 20) before using. 

32. How should the Spray Gun be held? 

It should be held perpendicular to the surface at all 
times — from 6 to 10 inches from the surface (See Fig. 21) . 
A simple method of determining the proper distance is 
shown in Fig. 22. 

[ 7 ] 



^,„^^^ Af/f CAP 




ju/jc a^O strain 
MA TEftlAL BEFORC 
USING fM GUN 



HOLD SPRAY GUN 

PERPENDICULAR 

TO SURFACE / 




CORRECT POS/TlOV 



UEASURINC DISTANCE 
TO HOLD CUN 





BEGIN STf>Off£ 

THEN PULL 

TRIGGER 



FIG 23 

SHOW/NG PROPER METHOD OF MAKING SPRAY GUN STROKE 



-3- 

RELEASE TfttCGEft 
SEEOffE COUPLET tftG 
i TfiOffE 



33. How is the proper stroke made? 

The stroke is made with a free arm motion, keeping the gun parallel to the surface 
at all points of the stroke (Fig. 23). The ends of the strokes are feathered out by 
"triggering" the gun, i.e., by beginning the stroke before pulling the trigger, and 
releasing the trigger just before ending the stroke (Fig. 23) . Arcing the gun results 
in uneven application and excessive over-spray at the ends of the stroke. 

34. How are comers sprayed? 

Spray within 1 or 2 inches of corner (Fig. 24). Then, holding gun sideways, catch 
both sides of the corner at once. Doing this otherwise (Fig. 25) wastes material 
and causes over-spray on the adjacent side. 

35. How fast should the g^un be moved? 

This depends on material being sprayed, rate of material flow and surface to be 
coated. Make adjustments for maximum speed consistent with your ability to 
operate gun and finish desired. 



SPRAY PAINTING CORNERS 




WRONG METHOD 



[ 8 ] 



36. What parts of the grun require lubrication? 

The Fluid Needle Packing, Air Valve Stem, Trigger 
Bearing Screw. The Fluid Needle Packing should be 
removed occasionally and softened with oil. The Fluid 
Needle Spring should be coated with grease or petro- 
latum (Fig. 26). 

37. How should the gun be cleaned? 

Remove cup from gun. Hold a cloth over openings in 
Air Cap and pull trigger (Fig. 27). Air diverted into 
fluid passage ways forces material back into container. 
Empty cup of material and replace with small quantity 
of solvent (Fig. 28). Spray solvent in usual way. This 
cleans out passageways. Then remove Air Cap and 
wash off Fluid Tip with solvent. Clean Air Cap by im- 
mersing in solvent and replace on gun. 

When using pressure feed (Fig. 29) , back up Regulator 
Adjusting Screw, release pressure from tank by means 
of Relief Valve or Safety Valve, hold cloth over air 
cap and pull trigger forcing material back into tank. 
Then remove fluid hose from gun and attach to Hose 
Cleaner* and run solvent through hose. Dry out hose 
with air. Spray some solvent through gun and clean 
Air Cap and Fluid Tip. Clean out tank and reassemble 
for future use. 

Note: It is a common practice to clean spray guns 
by placing entire gun in solvent. This should be 
avoided as solvents remove lubricants and dry out 
packings. 

Do not use caustic alkaline solutions for cleaning 
spray guns as they destroy aluminum alloys used in 
gun bodies and parts. 



'^l/L^ 



Aif> VALVE - 
PACK INC I FLUID 'needle 

I j \ PACKING 

POINTS OF LUBRICATION 



CLEANING SPRAY GUN 

CLOSE HOLES TO FORCE 
MATERIAL BACK i 

-J CONTAINER 




CLEAN CUP OUT THEN 
I SPRAr SOLVENT THROUCH Cl/N 



38. How should the Air Cap be cleaned? 

By simply immersing in solvent. If small 
holes become clogged soak in solvent. If 
reaming is still necessary use match stick, 
broom straw, or any other soft implement. 
Digging but holes with wire or nail may 
permanently damage cap. 

*A Hose Cleaner is a device for forcing a mixture 
of solvent and compressed air through fluid hose 
for the purpose of washing the interior. 

TROUBLES AND REMEDIES 

39. What causes fluid leakage from Fluid 
Needle Packing Nut? 

Loose Packing Nut or dry Fluid Needle 
Packing. Remove and soften packing with a 
few drops of light oil and replace. Tighten 
Packing Nut to prevent leakage but not so 
tight as to grip Fluid Needle. 

[ 9] 



CLEANING SPRAr GUN- PRESSURE FEED 




Note • _ 

release pressure 
in tank before 
blowing back 
material : 
shut off air to 

TANK 

OPEN RELIEF VALVE 
LOOSE N THUM B SCRE^^ 
OPEN LID SLlGHFLr 



FIG 30^-^^ 

P4CtflN6 NUr 



LACK OF 
LUBKICATit 



OiDT on 

BENT y4LV£ 
•"-3 STEu 



\ STEU J 



... .'V-:'' 

.,„, / VALV£ 

TOO TICHT BPOKEN SORING 

CAUSES OF AIR LFAH'AC£___ 



WRONC NEEDLE 

Size s^ MODN OH DdUACED 

FIG. 31 J><^f=LUID TIP OR 




40. WTiat causes air leakage from front of gun? 

Air Valve not seating properly (Fig. 30). Due to: 

1. Foreign matter on valve or seat. 

2. Worn or damaged valve or seat. 

3. Broken Air Valve Spring. 

4. Sticking Valve Stem due to lack of lubrication. 

5. Bent valve stem. 

6. Packing Nut too tight. 



BROKEN rtUID V3 PACKING NUT 
N££DLE SPRING TOO TIGHT 

CAUSES OF FLUID LEAKAGE 



41. WTiat causes 

Fluid Needle 



'PJRKJK qfi_Fj,^-r£^^jPfiAi.^-. 



LOOSE TIP OP 
OAUAGED SEAT 



LOOSE PACKING 

NUT OR OR I ED ^ 

OUT PACKING 



OBSTRUCT£0 
FLUID PASSAGES 



LOOSE OR DAUAGEO 
COUPLING NUT 



CLOCGED AIR VENT 



LOOSE OR DAUACED 
FLUID TUBE 



LACK OF SUFFICIENT 
U ATE RIAL IN COP 



FIG 32 
CAUSES OF JERK y 




fluid leakage from front of gun? 

not seating properly (Fig. 31). Due to: 

1. Worn or damaged Fluid Tip or 
Needle. 

2. Lumps or dirt lodged in Fluid 
Tip. 

3. Packing Nut too tight. 

4. Broken Fluid Needle Spring. 

5. Wrong Needle size. 

42. What causes a jerky or fluttering 

spray? 

Air leakage into fluid line (Fig. 
32). Due to: 

Applying to Pressure or Suction Feed 

1. Lack of sufficient material in 
container. 

2. Tipping container at acute angle. 



3. Obstructed fluid passage way. 

4. Loose or cracked Fluid Tube in Cup. 

5. lK)ose Fluid Tip or damaged tip seat. 

Applying to Sux:tion Feed only 

6. Too heavy material for Suction Feed. 

7. Clogged air vent in cup lid. 

8. Loose, dirty or damaged coupling nut on cup lid. 

9. Loose Fluid Needle Packing Nut. 
10. Fluid Tube resting on bottom of cup. 

43. \^Tiat causes defective spray patterns? 

1. Heavy Top Pattern (Fig. 35). Due to: 

(a) Horn Holes partially plugged. 

(b) Obstruction on top of Fluid Tip. 

(c) Dirt on Air Cap Seat or Fluid Tip Seat. 




NORttAL SPRAr PATTERNS 



r 10 ] 



2. Heavy Bottom Pattern (Fig. 36) . Due to: 

(a) Horn Holes partially plugged. 

(b) Obstruction on bottom side of Fluid Tip. 

(c) Dirt on Air Cap Seat or Fluid Tip Seat. 

3. Heavy Right Side Pattern (Fig. 37). Due to: 

(a) Right Side of Horn Holes partially clogged. 

(b) Dirt on right side of Fluid Tip. 

(c) On Twin Jet Cap, right jet clogged. 

4. Heavy Left Side Pattern (Fig. 38) . Due to: 

(a) Left side of horn holes partially clogged. 

(b) Dirt on left side of fluid tip. 

(c) On Twin Jet Cap, left jet clogged. 

5. Heavy Center Pattern (Fig. 39) . Due to: 

(a) Too low a setting of Spreader Adjustment Valve. 

(b) With Twin Jet Cap, too low atomizing pressure 
or material of too great viscosity. 

(c) With pressure feed, too high fluid pressure for 
cap's normal capacity. 

(d) Too large nozzle for material used. 

6. "Split Spray" Pattern (Fig. 40). Due to air and fluid 
not properly balanced. Reduce width of spray pattern 
by means of Spreader Adjustment Valve or increase 
fluid pressure. This latter adjustment increases speed 
and gun must be handled much faster. 




D£f£criV£ PATTERNS 



OEF£CT AT TOP 




IF PATTERH tS INVEPTED 

OBSrffucnoN IS on th£ 

AIR CAP 





REMEDIES: 

For Numbers 1 to 4: 

Determine if obstruction is on air cap or fluid tip. Rotate 
cap one half turn and spray another pattern. If defect 
is inverffed (Fig. 41) obstruction is on air cap, if not 
inverted it is on fluid tip. 

Clean air cap as described in No. 35. Check for fine burr on edge of fluid tip or 
for dried paint just inside opening. 

For Numbers 5 and 6: 

If adjustments are out of balance, readjust atomizing pressure, fluid pressure and 
spray width adjustment until desired spray is obtained. 

44. What causes "Orange Peel" finish (Fig. 42)? 

A common cause is improper thinner or too cheap a thinner. A thinner containing 
a high percent of low boiling or cheap solvents will cause "orange peel" regardless 
of how the material is applied. 
Other causes are: 



1. Insufficient atomization. 



[ 11] 



If GUN fS TtPfieo ^^^ ^^ 
Ar ANCLE FIQ 43 

\ MO/f£ MATERIAL 

\ IS APPLIED 



/ (STPEAKS^ 

/ J OCCUR 

k / HERE 

LESS UAFEiilAL 
IS APPLIED HCRE^ 



SAGS- roc I4UCH 




2. Gun too far from surface, 

3. Gun too close to surface — air has tendency to ripple 
surface. 

4. Material not thoroughly dissolved or agitated. 

5. With synthetics and lacquers, drafts in finishing room. 

6. With synthetics, too low humidity. 

45. What causes streaks in finish? 

Streaks are caused by: 

1. Tipping Gun (Fig. 43). One side of pattern hits sur- 
face from shorter distance causing more material to 
be applied at this point. 

2. Air cap or fluid tip may have dirt or burr on them 
causing heavy top or bottom pattern (see No. 44). 

3. "Split Spray" causing more material to be applied 
at top and bottom of pattern. Increase fluid pressure 
or reduce width of spray by decreasing Horn Air. 

46. What causes Runs and Sags in finish? 

1. Sags and runs (Fig. 44) are the result of too much 
material applied on the surface. Cut down fluid pres- 
sure or increase operating speed. 

2. Gun tilted at angle (Fig. 43). More material is sup- 
plied where pattern is closest to surface. 



47. What causes mist or fog (Fig. 45)? 

1. Over atomization due to: 

(a) Too high atomizing air pressure. 

(b) Wrong air cap for material used. 

(c) Wrong Fluid Tip for material used. 

(d) Fluid Pressure too low (Pressure Feed). 

2. Improper use of Gun: 

(a) Incorrect stroking. 

(b) Gun held too far from surface. 

48. What is "starving" the Spray Gun? 

By "starving" is meant insufficient air reaching Spray Gun. This may be due to 
(a) waste in Transformer too tightly packed, or clogged with rust and dirt, (b) 
air cocks of too small size, (c) clogged air lines, (d) air hose or pipe line of too 
small diameter, (e) inadequate air supply. 

49. What is the procedure in doing a touch-up job? 

1. Sand spot or scratch. Be sure a good feather edge is obtained. This should be- 
so gradual or finely tapered that metal cannot be detected from finish. 

2. Liberally build up with Primer-Surfacer, making certain that it extends beyond 
the feathered edges and is applied heavier than surrounding finish. 

3. Then sand until level and perfectly smooth. 

4. Apply finish material. 

5. A mist coat of thinner will smooth out rough spots. 

6. Then apply the firiishing coat. 

[ 12 ] 



i 



SPRAY GUN ACCESSORIES 

50. What is an Aii* Adjusting Valve? 

A valve (Fig. 46) which attaches to the air inlet of the 
gun and provides a means of regulating the atomizing 
pressure. 



51. What is a Fluid Cut-off Valve? 

A valve (Fig. 47) which attaches to the fluid inlet of the 
gun and provides a means of shutting off fluid at the 
gun. This permits gun to be detached from hose for clean- 
ing, etc. 

Some types have a "clean out" feature. If gun becomes 
clogged, this feature permits material to be blown back 
through exhaust port in valve. 



52. What is a Spray Gun Fluid Inlet Extension? 

A tube (Fig. 48) which brings the air and fluid hose 
connections together at the handle of the gun. 

53. What is an Adapter? 

A connection (Fig. 49), male one end and female on the 
other used to convert the connections on hose or equip- 
ment from one thread size to another. For example: 
^nH-20 thread to V4" pipe thread; %" pipe thread to "10- 
20 thread; %-18 thread to %" pipe thread. 

54. What is a Coupling? 

A connection (Fig. 50), male on both ends used to couple 
two pieces of hose together or to convert a female con- 
nection of one size thread to a male connection of an- 
other size thread. 

For example: 

0/46-20 Thread x 94f;-20 Thread 
^6-20 Thread x Sg-lS Thread 
%-18 Thread x %" Pipe Thread 
%" Pipe Thread x %" Pipe Thread 



A/ff ADJUSr/NG t/AH/£ 
NUT attachcs 
TO SPRAY 




FLUID CUr-OFF 
VALVE 

NUr ATTACHeS 

ro FLU/0 INLET 

ON SPRAY GU N 

3 L OW BACIf f£A rUR€ 

FLUID HOSe 

FIG 47 *rrA ches here 




FLUID INLET EXTENSION 



TUBE BRINGS 
AIR A NO FLU 10 
HOSE TOGETNER 




A DAP r£p - FEMALE TMREAO 

FIG 49 



<44LE THREAD 



COUPLING 



MALE THREADS 



FLUID STRAINER 
FIG 5/ 



STRAINER 
ASSURES CLEAN 
MATERIAL AT 

euN 



BRINGS AIR 
AND FLUID HOSE 
CONNECTIONS 

TOGETHER 




A IP OR FLUID VALVE 




THIS END 
ATTACHES 
TO EQUIPMENT 



55. What is a Fluid Strainer? 

A strainer specially designed for attaching to the fluid inlet of spray gun (Fig. 51), 
to prevent any foreign matter from entering fluid passages and being deposited on 
the work. 



56. What are Air and Fluid Valves? 

Air and Fluid Valves are attached to pressure tanks, compressing outfits or other 
pieces of equipment to provide an outlet connection for hose, etc., and some means 
of turning on or off the air or fluid. 

[ 13 ] 



LID SCtfEWS 



CLASS OR 
USTAL CUP 



SCREW TYPE CUP 
ATTACHMENT 




ffINC 

PRE VEN TS 
INJURY TO 
'CUP 



CLAMP TYPE CUP 
ATTACHMENT 



FIG 54 

A TERI 



•G 



CLAMP TYPE CUP 

ATTA CM MEN T Wl TH 

PAPER CUP 




SAFETf ^^_^ V~ 



EQUALIZED PRESSURE 
TYPE CUP 



Part II. MATERIAL CONTAINERS 

57. What are Material Containers? 

Material Containers are metal or glass (sometimes paper) 
vessels connected to the spray gun which serve as sup- 
ply reservoirs for the material to be sprayed. 

58. How many types of Material Containers are there? 

There are three: Cup, Tank, and Bucket types. 

59. \Miere are Cup Containers used? 

They are used where a variety of colors and materials 
in comparatively small quantities are to be sprayed. 

60. How many types of Cup Containers are there? 

There are three: Suction, Gravity, and Pressure Feed 
types. 

61. How are Suction Feed Cups attached to Lid? 

They have either a screw top (Fig. 52) or a clamp top 
(Fig. 53 and 55). Small material containers sometimes 
have no lids and attach directly to the gun (Fig. 54). 

62. Wlien are Suction Feed Cups recommended? 

For small quantities of light and medium weight materials 
adaptable to suction feed, such as lacquers, synthetic 
enamels, stains, bronzes, latex, etc. 

63. ^Tiere are Gravity Feed Cups used? 

They are usually used on Artists' Air Brushes, Decora- 
tors' Guns, small Touch-up Guns, etc. 

64. How are Gravity Feed Containers attached? 

They are usually of small capacity and are attached di- 
rectly to the top or side of gun (Fig. 56). 

65. Where are Pressure Feed Cups recommended? 

For small quantities of enamels, plastics, and other ma- 
terials too heavy for suction feed, and where fine adjust- 
ment and speed of application are desired. 

66. How are Pressure Feed Cups classified? 

Into two classes: Equalized Pressure Type (Fig. 57) and 
Regulator Type (Fig. 58). In the Equalized Pressure 
Type, control of pressure is not provided. Pressure for 
gun is same as pressure on material. No accessories are 
provided except a Safety Valve. The Regulator Type 
allows for regulation of fluid pressure. It has the follow- 
ing accessories (Fig. 59): An Air Regulator to control 
pressure on the material, a Valve to control the air to 
the gun, a Release Valve to release pressure from the 
cup, and a Safety Valve to prevent excessive pressure 
in the cup. 

[ 14 ] 



67. What are the advantages of the Regulator Type? 

With this type cup, any type of material can be sprayed 
with a fine degree of control and accuracy. In operation 
it is a miniature pressure feed tank. It may be used for 
tests, experiments, etc., since it can be used for duplicat- 
ing production finishing operations. 

It is particularly adaptable for applying modern decora- 
tive effects and finishes such as stipple, spatter, veiling, 
and the like produced by means of the pressure feed cup 
in combination with the Decorator's Spray Head (See 
No. 18). 

68. Where are the Equalized Pressure type used? 

Where pressure control is not of major importance. They 
are usually used with small units of limited capacity and 
pressure. 

69. What are Pressure Feed Tanks and where are they 
recommended? 

Pressure Feed Tanks are material containers that pro- 
vide a constant flow of material at uniform pressure to 
the spray gun. They range in size from two-gallon to 
sixty-gallon capacities. Fundamentally they consist of 
a shell, clamp-on lid, fluid tube, outlet valves, fluid header 
and safety valve. They can be had with top or bottom 
outlet and various accessories. 

In almost every case where continuous production is 
maintained, pressure feed tanks provide the most practi- 
cable and economical method of feeding material to the 
spray gun. The flow of material is more positive, uniform, 
and in greater volume than with any other method. 

70. How many types of tanks are there? 

There are two types: Regulator Type (Fig. 60) and Equal- 
ized Pressure Type (Fig. 61), The Regulator Type is 
equipped with Pressure Regulator, Safety Valve, Release 
Valve, Pressure Gauge, etc., while the Equalized Pressure 
Type hes only a Safety Valve and a Release Valve. 

71. What are the advantages of the Regulator Type? 

They offer the advantage of conveying large quantities of 
materials to the spray gun under constant and accurate 
control of fluid pressure. 

72. What is a Single Regulator Tank? 

A tank equipped with one regulator which serves to 
regulate only the fluid pressure in the tank (Fig. 62). 

73. What is a Double Regulator Tank? 

A tank equipped with two regulators (Fig. 63) , providing 
independent regulation for the air pressure to the Spray 
Gun and the fluid pressure in the tank. 

[ 15 ] 




REGULArofi ryp£ cup 



4lf> ADJUSTlfiC 

y4iy£ coNrtfOLS 

AIR rO SPtfAr GUN 



in Die A res 

PR£SSUfte 
IN CUP 



ff£L€AS£ AHD 

SAF£rr 

LV£ 





REGULATOR TYPE 
TANK 




EQUALIZED PRESSURE 
TYPE TANK 



RECUL A rOR 
CONTROLS 

PRESSURE 
IN TANK 



CAuce 

/NDI CAFES 
PRESSURE 
IN TANK 




CAUCE INDICATES 
PRESSURE 
TO CON 




REQULATOR 

FIG 63 CONTROLS 

AIR TO CUN 

PECULATOR 
CONTROLS PRESSURE 
IN TANK 



ENTERS MERE- 



SINGLE REGULATOR TANK 



DOUBLE REGULATOR 



CO, 



X=^ 



AIR MOTOR DRIVE 
FOR AGITATOR 




S 



ELECTRIC MOTOR DRIVE 
FOR AGITATOR 



"alia 



7^ 



BELT DRIVE 
FOR AGITATOR 




INSERT CONTAINER 



74. \Miere are Double Regulator tanks used? 

On operations where independent fluid and air pressure 
control is essential. 

For example, Internal Mix Spray Guns with Air Com- 
pressing Outfits whose air pressure is in excess of that 
required for either air or fluid pressure. Double Regula- 
tion permits varying fluid and atomization pressures to 
meet any operating conditions. Fluid pressure may be 
higher or lower than atomizing pressure, depending upon 
height gun is raised above tank, size of hose, speed of 
operation, length of hose, etc. 

75. Where are Equalized Pressure Tanks used? 

Where pressure control is not of major importance. They 
are usually used with small units of limited capacity and 
pressure. 

76. Of what materials are tanks constructed? 

They are made of steel, heavily galvanized inside and out 
(cheaper styles are sometimes painted outside). Shells 
are specially coated inside or lined with special material 
when designed for use with abrasive or corrosive sub- 
stances. 

For example, tanks for porcelain enamel and other 
ceramic materials may have a special wear-resistant 
shell; tanks for latex may be heavily tinned. 

77. WTien are tanks equipped with Agitators? 

When materials require frequent or constant agitation. 
Mechanical Agitators eliminate the necessity of operator 
stirring paint. 

78. How many types of Agitator Drives are there? 

There are three: Air Motor (Fig. 64). Electric Motor 
(Fig. 65), and Belt Drive (Fig. 66). 

Air Motor Drives are practically universally used on all 
standard size pressure feed Unks. Having no electrical 
connections, no hazard is involved. Speed is variable. 
Electric Motor Drives are used on all standard size pres- 
sure feed tanks. For use in hazardous conditions, they 
must be supplied with a permanent connection in ac- 
cordance with National Electrical Code. 
Belt Drive may be used where tank is located near line 
shaft. 

[ 16 ] 






79. What are Insert Containers? 

These are metal pail-like vessels (Fig. 67) that are set 
inside the tank and filled with material, instead of pour- 
ing it directly in the tank. This eliminates cleaning out 
the tank, and is convenient in changing from one color 
or one material to another. They also permit several 
batches of material to be mixed ahead. 

80. Where are Gravity' Buckets used? 

Gravity Buckets (Fig. 68) are used very little today, and 
are practically obsolete. 

81. What are the disadvantages of Gravity Buckets? 

They are (a) cumbersome to handle (b) must be securely 
fastened (c) present a hazard (d) material flows only at 
gravity rate — which varies with volume and viscosity of 
material and height of container (e) inconvenient for 
filling (f) speed of production is limited (g) on tall 
objects flow of material is freer when spraying bottom 
than at top. 



SAF£rr 

BLOOf ANO 
TACKLE 




GRAVITY BUCKET 



Part III. HOSE AND HOSE CONNECTIONS 



82. What types of Hose are used in Spray Painting? 

Two types: Air and Fluid Hose. Air hose has red rubber 
cover or orange braid cover; Fluid hose is black. The 
braid covered tubing is used on low priced units. 

83. How is hose constructed? 

Braid covered tubing as shovm in Fig. 69 is simply 
tubing with braid woven around it. One braid construc- 
tion consists of an inner tube (Fig. 70) , a braid insert, and 
an outside cover all vulcanized into one. Two braid con- 
struction consists of an inner tube (Fig. 71), a braid 
insert, a separator, another layer of braid, and, finally, an 
outside cover all vulcanized into one. 

84. What type of Inner-tube is used in Fluid Hose? 

A special solvent resisting liner which is practically im- 
pervious to the action of all common solvents in paints, 
lacquers, and other finishing material which readily at- 
tack ordinary rubber composition hose. 

85. What sizes of Air Hose are used? 

(a) From Compressing Outfit or Transformer to gun: ^e" 
(Fig. 72) LD. (inside diameter) is recommended; 
1/4" (Fig. 72) ID. may be used with small Guns, 
provided length does not exceed 12'. 

(b) Compressing Outfit to Pressure Feed Tank: Use 
7A6"I.D. (Fig. 72). 

[ 17 ] 



-INNER TUBE 



-BftA/O COVE If 



BRAID COVERED TUBfNG 



INNER TUBE 

BRA 10 INSERT 

OUTSIDE COINER- 

FIG 70 
ONE BRA 10 CONSTRUCTION 




%f in ^ IM 

AIR HOSE SIZES 



FIG. 




'TM 70 LBS P/?£SSt/fi£ 
\r TffANSrOf>U£l) 



rou e£r o^ir 47^ 

LBS. AT SPRAT CUM mLET 



PfiESSURB DROP IN AIR HOSE 




USING fS FE£T 

^ IN. A in Mose 



86. What happens if too small Hose is 
used? 

Spray Gun is "starved" due to exces- 
sive pressure drop in atomizing air 
pressure. 



87. WTiat is pressure drop? 

Pressure drop is the difference be- 
tween the pressure at the point where 
the Hose is connected and the actual 
pressure gauge reading at the Spray 
Gun {Fig. 73) . The amount of pressure 
drop which occurs in various lengths 
of I4" and ^/\{" Air Hose will be ob- 
served from the accompanying table. 



Too often a spray gun is blamed for functioning improperly, or a material is con- 
sidered of inferior quality, when the real cause of the trouble is an inadequate 
supply of compressed air at the gun. Frequently operators believe they are using 
pressures as high as 100 lbs. (a much higher pressure than ever required), but 
investigation reveals that, due to improper size hose, pressure is inadequate for 
proper atomization. There are, of course, other causes for loss in volume and 
pressure such as clogged air lines, clogged Air Transformer, etc. (See No. 48). 



88. What sizes of Fluid Hose are used? 

(a) Production Finishing — Large Guns — %" I.D. 

(b) Maintenance Finishing — Large Guns — W I.D. 

(c) Maintenance Finishing — Small Guns 

such as used on V^, % and V2 H.P. Outfits— ^He" 



ID. 



TABLE OF DROP IN AIR PRESSURE 

To be expected from various lengths of V4-inch and ^lo-inch Air Hose when used 

with Spray Gun equipped with Air Cap consuming approximately 12 cubic feet of 

air per minute at 60 pounds pressure 



Size of Air Hose 
IcLside Diameter 


Air Pressure Drop At Spray Gun 


6-foot 
length 


10-foot 
length 


15-foot 
length 


20-foot 
length 


25-foot 
length 


60-foot 
length 


1/4-inch 
At 40 lbs. pressure 
At 50 lbs. pressure 
At 60 lbs. pressure 
At 70 lbs. pressure 
At 80 lbs. pressure 
At 90 lbs. pressure 


Lbs. 
6 

9 

12'4 
14 


Lbs. 
8 
10 
12H 
14H 
16H 
18»i 


Lbs. 
9H 
12 

14H 
17 

19H 
22 


Lbs 
11 
14 
16»i 
19H 
22H 
25 '4 


Lbs. 
\2H 
16 
19 

22H 
25H 
29 


Lbs. 

24 

28 

31 

34 

37 

39H 


5/16-inch 
At 40 lbs. pressure 
At 50 lbs. pressure 
At 60 lbs. pressure 
At 70 lbs. pressure 
At 80 lbs. pressure 
At 90 lbs. pressure 


2' 4 
3 

5H 
6H 


2% 
4H 
6^i 

7H 


3'i 

4 
5 
6 
7 
8H 


3H 

4>^ 
5H 

6!i 

8 

9H 


4 
5 
6 

^H 
lOH 


10 

HH 

13 

14H 

16 



f 18 ] 



HOS£ 
CONMECriON 
BODY 



g 

Pin 7A <=^ 



EXPANDER SCREW 
TYPE CONNECTION 



HOSE 

CONHECTtotf 

aODiES 





COM PRESS /ON RING 

TYPE CONNECTION 



QUICK DETACHABLE 
TYPE CONNECTION 



89. How many types of Hose Connections are there? 

Three types: Expander Screw (Fig. 74), Compression Ring (Fig. 75), and Quick 
Detachable (Fig. 76) which attaches in either of the above ways but incorporates a 
quick detachable body. 

Some advantages of Compression Ring TVpe are as follows: 



They are Economical because: 

(a) All parts may be used over and 
over. 

(b) They save the hose — no pinching 
or chewing cover. 

(c) They are air tight — no leaks be- 
tween connection and hose. 



They are Convenient because: 

(a) Easy to put on and take off hose. 

(b) No special tools required. 

(c) No proiections to catch or snag. 

(d) Available in either male or female 
type in all thread sizes common to 
air operated tools. 



90. Are these Hose Connections removable? 

Yes, parts are easily removable and all parts are re-usable. 

91. How are these Hose Connections applied? 

(a) Cora-press^on Ring Type 

1. Slip Sleeve and Compression Ring over end of hose (Fig. 77). 

2. Hold Body in vise. 

3. Push hose into body as far as it will go. 

4. Now slide Ring up to body. 

5. Bring sleeve over ring and attach to body. Tighten with wrench. 

(b) Expander Screw Type 

1^ Slip Sleeve over hose until it shoulders against hose (Fig. 78) . 

2. Hold Sleeve in vise. 

3. Now turn Expander Screw into Sleeve until threads are just covered. 



CONNECTION BQOr 





CONNECTION BODY 

MOLD SLEEVE IN VISE 
AND TtQHTEN CONNECTION 
BOOr WITH tVRENCH 




EXPANDER SCREW TYPE 



[ 19 ] 



Part IV. AIR TRANSFORMERS AND CONDENSERS 



*f C UL 4 TED 

pnessuoE 

GAUGE 




UAIN LINE 
PRESSURE 
GAUGE / 



\M^ 



RECULATCD 
PI>ESSUf>£ OUTLET 
^AL^ES FOR SPRAr GUNS 



UAIN LINE PRESSURE 
OUTLET HALVES FOR 

DUSTER GUNS ere. 




AIR IS FILTERED . 
AND CLEANED AS 
J 7 PASSES TM ROUGH 
FIL TER 



c 



iL Ano uonr^tit I 
DROP 'O V. I I 

torrotJ \I I 
FIG. 60 J H^ 



A IP TRANS^CPMEff 




92. \\Tiat is an Air Transformer? 

An Air Transformer is a device which condenses 
air, oil and moisture; regulates, filters and strains 
the air; indicates by gauges main line and regu- 
lated pressures; and provides outlets to which 
spray giins, dusters, etc. can be connected. 

93. Where are Air Transformers used? 

In all finishing or refinishing departments where 
a supply of moisture-free, regulated air is re- 
quired. 

94. What zire the principal parts of an Air Trans- 
former? 

An Air Regulator (Fig. 79 and 80), Pressure 
Gauges, Condenser, Filter Pack, Baffles. Outlet 
Valves, and a Drain Valve. 

95. How does the Air Transformer operate? 

Oil and moisture are collected by the Baffles and 
Filter Pack (Fig. 80) allowing only clean, dry 
air to reach the spray gun. The Air Regulator 
provides a positive control of air, insuring uni- 
form regulated pressure at spray gxin. Gauges 
indicate main line and regulated pressures, and 
Valves provide outlets for Spray Guns and other 
equipment. 

Some later model Transformers use a metal disc 
filtering unit in place of the Filter Pack men- 
tioned above. On this type the unit requires only 
periodic removal for cleaning. 

96. How should Transformer be installed? 

fa) At least 15' from Compressing Outfit. 

I Take-off should be from the top of the air 
line (Fig. 81). 

(c) Piping should slope toward a Drain Leg in- 
stalled at the end of the line or the end of 
each branch. 

(d) Use piping of sufficient size for the volume 
and length of pipe used (See Pipe Recom- 
mendations in Question No. 120). 

Pipes should be as direct as possible. If a large 
number of fittings is used, the recommended 
length should be reduced correspondingly. 

Automatic Drains which eliminate necessity of 
hand draining are available for attachment to 
Air Transformers. 

[ 20 ] 



J> 



PIPE PECOMMENDAnONS 

I'/i AN& i HP OUTFITS 

UIN '/i /* UP TO 50 FT. 

OV£P $0 FT }i fN. 
J AND S H P OUr^tTS 

A*fN % IN. UP TO 100 FT. 

0¥£R iOQ FT. I IN 

LINE 





AIR TPANSFOffUEfi 



^ 



«1 



DRAIN t£C ^ 




SHOWING PROPER iNSFALLATJON OF AIR 
COMPRESSING OUTFIT, PIPING ETC 



DRAIN H£R£ DAILT 



97. How often should Transformer be drained? 

Once a day or more frequently if necessary in humid weather. 

98. What should be checked if moisture passes through Transformer? 

(a) Drain Transformer, Air Receiver and air line of accumulated moisture. 

(b) Transformer located at least 15' from Compressing Outfit. 

(c) Main Air Line should not run parallel to steam or hot water piping. 

(d) Compressor should not be located near steam outlet, etc. 

(e) Outlet on Compressing Outfit should be near top of Air Receiver. 

(f) Check for damaged cylinder head or leaking gasket, if water cooled com- 
pressor. 

99. What causes pressure to "creep" up after adjustment? 

(a) Valve Assembly (Fig. 82) loose in Body Casting. 

(b) Valve should be set %4" above face of casting (Fig. 82). 

(c) Valve Seat (Fig. 82) may be dirty or worn. 

100. What causes excessive pressure drop on Main Air Line Gauge? 

(a) Compressing Outfit too small. 

(b) Compressing Outfit not functioning properly. 

(c) Leakage in air line or partially 
opened valves. 

(d) Air line too small for volume of 
air handled. 

(e) Filter (or Waste) Pack (Fig. 83) 

clogged or packed too tightly. 

101. What causes air to leak from small 
hole in Regulator Cap? 

An improperly seated or broken Dia- 
phragm (Fig. 82). 



Boor CASTING 




[ 21 ] 




B* fFtes rrJ^ii 



nEuove 

LOWeff CAP 

Ff>QU 
CONOeNS£R 
TUBE 



LIFT SCB££H 



REPLACE. 
FILTER PACIC 
IH INNER 

TUBE 





REPLACE FILTER PACK 



'^ 



V 



AIR CONDENSER 



102. How is Filter Pack replaced? 

Remove lower cap from Transformer. Pull out Inner Tube (Fig. 83). Lift out 
screen and Filter Pack (Waste Pack). Replace Filter Pack, which should always 
be loosely packed. 

103. What is an Air Condenser? 

An oil and moisture separator (Fig. 84) used where regulated air is available and 
cleaning only is necessary. 



Part V. AIR COMPRESSING OUTFITS 

104. What is an Air Compressing Outfit? 

A mechanism designed to supply compressed air continuously at a predetermined 
maximum pressure and a minimum volume in cubic feet per minute. 

105. How many Types are there? 

Two general types: Single Stage and Two Stage. These can be further sub-divided 
into many types some of which are as follows: 

(a) Electric Motor or Gas Engine Driven. 

(b) Portable or Stationary. 

(c) Unloader or Pressure Switch controlled. 

(d) Horizontally or Vertically mounted tanks. 

(e) Air or Water cooled compressor. 

106. Wliat is a Single Stage Outfit? 

An Outfit having one or two cylinders (Fig. 85) in which the air is drawn from 
the atmosphere compressed to its final pressure then delivered through an after- 
cooler to the Air Receiver. 

107. Where are Single Stage Outfits used? 

Usually where maximum pressures do not exceed 100 lbs. 

108. Are Single Stage Outfits good for more than 100 lbs.? 

They can be used, but from an efficiency and economical standpoint, they are 
not as practical. 

[ 22 ] 



I 



S/^GL£ STAGE 



r°^ r°=S (°^ r°^ 




ro 4fft 

RECEIVER 



TWO 

LOW PRESSURE 

OR 
FtRST STAGE 



^H^akP- 



STAGE 

HICH PRESSURE 

OR 

SECOND S7ACE 

,P>Pl. 




INTERCOOLER 



AFTERCOOLER^ 



109. What is a Two Stage Outfit? 

A Compressor which has a large cylinder (Fig. 86) where the air is first com- 
pressed to an intermediate pressure, then delivered through an intercooler to a 
small cylinder where it is compressed to the final pressure, from which it is de- 
livered through an aftercooler to the Air Receiver. 



110. Where are Two Stage Outfits used? 

Usually where maximum pressures exceed 100 lbs. 

111. Are Two Stage Outfits more economical? 

Yes, generally where requirements are for more than 100 lbs. pressure. The 
advantages are: 

(a) More efficient, i.e., more air per kilowatt hour. 

(b) Higher pressure permits faster operation of tools, etc. 

(c) More air is stored in Air Receiver. 

(d) Greater air delivery permits use of larger, faster equipment. 

112. How much more air is stored at 200 lbs. pressure than at 150 lbs. pressure? 

About 1/^ more as shown in the following table. 



Tank Size 

16x40 
20x48 
20x60 



Capacity 
Cu. Ft. 

4.97 
9.34 
10.88 



Cu. Ft. 
At 125 lbs. 

42.30 
79.47 
92.51 



Cu. Ft. 
At 150 lbs. 

50.77 
95.37 
111.0 



Cu. Ft. 
At 175 lbs. 

59.22 
111.2 
129.5 



Cu. Ft. 
At 200 lbs. 

67.69 
127.10 
148.0 



113. Where are Engine Driven Outfits used? 

(a) Where electric current is not available. 

(b) Where outfits are to be moved in localities where there are different current 
characteristics. 

(c) In localities where insufficient current is supplied. 

[ 23 ] 



HANDLE 
fO/> uoyf 

OUTFIT 



£L£:CTR/C MOTOR 

ALSO SUPPLIED 
rflTH CAS £NGtN£S 



AUICMACnC UN LOADER 
MECHANISM 

ALLOCS ourfir to ftuN 

IDLE AFTEP MAXIMUM 
fPESStIPE li PEACHED 



I STAnONARy OUTFIT \ 
CENTRIFUGAL PRESSURE S W/ TCN 




PRESSURE RELEASE 

AlLOtrS COMPPESSOft 
TO PUN FPEE UHTIL 
NOPMAL SPEED IS 
ATTAINEO 



LARGE AIR RECEIVER 

PPOVIDES AUPLE 
AlP srOPACE 



SMALL AIR 
RECEIVER 

SUALLEP PESEPVE 
UT MOPE COMPACT 



WHEELS 

EASILY MOVED 
ABOUT 




114. How tlo stationary and Portable Outfits differ? 

A Portable Outfit (Fig. 87) is equipped with a handle and wheels for moving about, 

has only a small Air Receiver for compactness, and is controlled by an Automatic 

Unloader. 

A Stationary Outfit (Fig. 88) has feet for mounting, a large Air Receiver for 

storage, and is controlled by a Pressure Switch or an Automatic Unloader. 

(Where this type must be moved from place to place, a castered truck is provided.) 

115. How should a Stationary Outfit be installed? 

(a) It should be wired by a competent electrician in accordance with National 
Electrical Code. 

(b) Overload protection should be furnished. 

(c) It should be located in a cool place— at least a foot from wall, where it will 
receive dry, clean air. Where permissible it is recommended to have intake 
of compressor piped to outside of building (Fig. 89) to insure clean, cool air. 

(d) Main Line Pipe should be of sufficient size as shown below: 

IV2 and 2 H.P. Outfits Minimum V^" up to 50 ft. 

Over 50 ft., 3/4". 
3 and 5 HP. Outfits Minimum 3/4" up to 200 ft. 

Over 200 ft., 1". 

116. How do Unloader and Pressure Switch control differ? 

(a) An Unloader (Fig. 90) acts on the Compressor, automatically opening tlie 
Intake Valve allowing Compressor to run idle. 

(b) A Pressure Switch acts on the Motor, automatically shutting off the Motor 
and Compressor at a predetermined maximum pressure and automatically 
starting it again at a predetermined minimum pressure. 

117. When should a Compressing Outfit be replaced? 

(a) When old age has decreased efficiency of the outfit, or 

(b) When the outfit is unable to supply sufficient air for requirements, or 

(c) When time from cut-in to cut-out shows waste of electrical energy, and the 
increased overhead would pay for a new outfit (See No. 118). 

118. How long should it take (o pump from cul-in to cut-out on different outfits? 

For pumping time of several different size outfits see chart on page 25. 

[ 24 1 



Outfit H.P. Tank Cut-in Cut-out 



Single StaRe 

Single Stage 

Single Stage 

Single Stage 

Two Stage 

Two Stage 

Two Stage 

Two Stage 



1/2 
1 
3 
5 

% 
1 
3 
5 



16 X 40 
16 X 40 
20x48 
20x48 
20 X 48 
20x48 
20x48 
20x60 



120 lb. 
120 lb. 
120 lb. 
120 lb. 
160 lb. 
160 lb. 
160 lb. 
160 lb. 



150 lb. 
150 lb. 
150 lb. 
150 lb. 
200 lb. 
200 lb. 
200 lb. 
200 lb. 



Time to 
pump 
cut-in to 
cut-out 
5.76 min. 
3.27 min. 
1.92 min. 
1.17 min. 
9.66 min. 
6.57 min. 
2.42 min. 
1.74 min. 



1 1 



AUTOMATIC 



nHCH MAX I, 

poessufte 

PCACHCO- 




PILOr HOLDS 

INTAKE \\ ' 
V*L^e OPEN 

PILOT 1/ I . ^ 

Va W /coupfteaoft 

*=* PUN I IDLE UNTIL 

PPESSUPC DROPS 
^BELOW UINIUUU 
PRESSURE SErriNG 



AIR RECEIVER 



119, What size Compressing Outfit should be selected? 

One that will supply more air than is actually required. 
This allows for margin or reserve for peak loads, and 
future additional equipment. 
An undersized outfit will cost more due to: 

(a) Time wasted waiting for outfit to build up to re- 
quired pressure. 

(b) Longer operating periods. 

(c) Greater possibility of breakdown, and 

(d) Additional labor saving tools cannot be used. 



120. How can the proper size be determined? 

In selecting a compressing outfit of the proper size, 
certain factors should be taken into consideration: 

1. List all tools to be used. Divide them into those which 
may be operated continuously, such as Spray Guns, 
and those which are operated intermittently and for 
brief periods only, such as service station tools. 

2. Obtain air capacities in cubic feet per minute of all 
tools listed. The accompanying chart gives approxi- 
mate requirements of various tools. As these may vary considerably, it is sug- 
gested that actual requirements be obtained from manufacturer. For tools not 
listed, approximate requirements can be obtained frofn the table on Page 26, 
which gives amount of air that will pass through orifices of various sizes at 
different pressures. 

3. Considering man power available, add up capacities of all tools that can be 
operated simultaneously. This figure represents peak requirement, and Com- 
pressor capacity need not exceed it unless provision is to be made for addi- 
tional tools. 

4. Determine maximum pressure required by tools. The cut-in pressure of the 
outfit chosen will have to be high enough to operate tools requiring highest 
pressures. 

5. Knowing capacity and pressure required, select Compressor, keeping in mind 
that the displacement rating of a Compressor is not the same as actual volume 
of air delivered. The actual volume delivered will depend on the volumetric 
efficiency of the outfit, i.e., the ratio of the actual output to the theoretical 
output, 

121. How much air do tools generally use? 

The accompanying chart lists some of the common tools and their consumption. 

[ 25 1 



COMPffESSOIf 
AIR STRA 

ATTEffCOOLER 

AIR RECEIt'ER 

PRESSURE CAU 
SAFETY VALVE - 
OUTLET VALVE 



nTERCOOlER 

CHECK VALVE 




UOroR OR 
ENQIHE 



PRESiURE RELEASE 



PRINCIPAL 
COMPRESSING 



PARTS OF 
OUTFITS 




REQUIREMENTS FOR AIR OPERATED EQUIPMENT 

Cubic Feet of 
Air Per Minute 

Gasoline or Oil Pump— Pressure or Piston Type. 1 

Gasoline Pump — Air Motor Type 4 

Air Meters and Hose Lines for Tires l^^S 

Tire Inflation (per tire line) 1^ 

Tire Changers and Spreaders .1-4 

Rim Stripper ... 6 

Pneumatic Garage Doors (each operation) 2 

Air Doors 2-3 

Testing Radiators 1 

Spark Plug Testers Va, 

Carbon Remover 3-5 

Valve Grinding 2 

Blow Gun for Cleaning Engine 3-7 

Blow Pipe Nozzles (intermittent use) 2-5 

Oil Spray Guns ( motor cleaning) .6 

Spring Oiling Guns 3-7 

Air Springs ( shock absorbers) (per line) 14 

Air Lift Grease Rack 6-10 

Grease Guns 1-4 

Brake Testers V^hr^ 

Air Brake Reservoir (per line) XVz 

Air Hammer ( garage type) 8-12 

Paint Spray Gun .2-10 

Pneumatic Car Washer Nozzles 4-16 

Pneumatic Rubber is 

Body Sander - 

Body Polisher - 

Vacuum Cleaner for Interiors 

122. How can requirements be calculated for tools not listed? 

Measure diameter of orifice and determine air consumption from chart below: 




FIG 93 

DIAPHRAGM 



TY 



Flow of Air Through Round Orifice in C.F.M 



Cubic feet per minute) 



Orifice 


301b. 


401b. 


501b. 


601b. 


801b. 


100 lb. 


1251b. 


1501b. 


200 lb 


W 


.632 


.77 


.914 


1.05 


1.33 


1.61 


1.97 


2.33 


3.07 


Mg" 


2.52 


3.07 


3.64 


4.2 


5.32 


6.45 


7.85 


9.20 


22.2 


y^" 


10. 


12.27 


14.5 


16.8 


21.2 


23.5 


31.4 


36.7 


48.7 


y^r 


40. 


49.09 


58.2 


67. 


85. 


103.2 


125.5 


147. 


190.8 



[ 26 ] 



F£Aru/?£S OF AIR COMPRESSOR 



(NTAKE VALVE 



REMOVABLE AS 
AN ASSEMBLY 



QUICK ACTING VALVE 



OIL PROOF PISTON 
AND RING ASSEMBLr" 



PISTON AND CONNECTING 
ROD ASSEMBLY 



ENCLOSED CRANKCASE- 



RING AND CENTRIFUGAL ^ 
FORCE OIL SYSTEM' 



CRANK SHAFT - 



SPUN BABBIT^ 
BEARINGS 



EXHAUST VALVE 



REMOVABLE AS 
AN ASSEMBLr 



FINNED HEAD 

AND CYLINDERS 




K 



AIR STRAINER 



FINNED INTERCOOLER 



-^CENTRIFUGAL 
PRESSURE RELEASE 



UNIT CYLINDERS 
AND CRANKCASE 



123. What is displacement of a compressor? 

Theoretical discharge (in cubic feet) of air in one minute. 

124. How can the displacement be computed? 

By the following formula: 

Bore X Bore x .7854 x Stroke x R.P.M. x No. of Cylinders _ Displacement 
1728 in C. F. M. 

Bore and Stroke measurements in the above formula are in inches. The above 
formula applies to Single Stage Compressors, but can be used for Two Stage 
Units if the small High Pressure Cylinder is not computed. 

125. What is the volumetric efficiency of a compressor? 

The ratio of the actual output to the theoretical output. 

126. What is the average volumetric efficiency of Single Stage Outfits? Of Two Stage 
Outfits? 

„ (Maximum working pressure 150 lbs. 60% 

bingie btage: j ^^^^^^ working pressure 100 lbs. 70% 

Two Stage: Maximum working pressure 200 lbs. 80% 

127. WTiat, then, is the "delivery" of a compressor? 

The actual output of air furnished. This can be obtained by multiplying the dis- 
placement by the volumetric efficiency. 

Example- A single stage outfit (for 100 lb. service) has a displacement of 10 C.F.M. 
Figurmg it is 707o efficient at this pressure, the delivery will be 10 C.F.M. x 70% 
or 7 C.F.M. 

[ 27 ] 



128. What are the principal parts of an Air Compressing Outfit? 

The principal parts (Fig. 91) are: 

1. Air Compressor — pumps or compresses the air, 

2. Motor or Engine — drives Air Compressor. 

3. Air Receiver or Storage Tank — stores the compressed air. 

4. Check Valve — prevents leakage of stored air back through compressor. 

5. Unloader or Pressure Switch — automatically controls pressure. 

6. Centrifugal Pressure Release — relieves motor of starting against load. 

7. Motor Starter — a manual or automatic switch for starting motor. 



UMLOADCR 

PILOT 
MOLDS 

INT A tee 




pf>es$'jf>e 
sriNc 



DJUSTABLC 

FOfi 
VARIOUS 
i^^^'r^PRESSURiS 



UNLOADER PILOT 



VALVe 

PLUNCeH 
HOLDS 

INTAKE 
VALVE 
OPEN 




ki5?i>; 



UNLOADER MECHANISM 



129. How many Types of Compressors are there? 

There are many types of which the most common are: 

1. Rotary Type (Fig. 92) . Air is compressed by vanes. It 
has very small capacity and is good only for low 
pressures. 

2. Diaphragm Type (Fig. 93). Air is compressed by up- 
and-down motion of diaphragm. Used only with frac- 
tional Motors. 

3. Piston Type (Fig. 94). Air is compressed by Piston 
driven by Crankshaft. This is the type that is almost 
universally used. 

130. What features should an Air Compressor have? 

It should have the following features (Fig. 95) : 

(a) Removable Valve Assemblies. 

(b) Quick Acting Valves. 

(c) Oil Proof Piston and Ring Assembly. 

(d) Honed Cylinders. 

(e) Unit Cylinders and Crankcase. 

(f) An efficient cooling system consisting of finned 
Aftercoolers, and finned Cylinders and Head. 

(g) Enclosed Crankcase. 

(h) A positive oil system such as Ring and Centrifugal 

Force System, 
(i) Spun Babbit Bearings. 
(j) Ball Bearings. 



131. What are the principal parts of a Compressor? 

Intake and Exhaust Valve Assemblies, Cylinder and Crankcase, Crankshaft, Piston 
and Connecting Rod Assembly, and Air Strainer. 

132. How does an Automatic Unloader operate? 

When maximum pressure in the Air Receiver is reached, the Unloader Pilot (Fig. 
96) operates the Unloader Mechanism (Fig. 97) automatically holding open the 
Intake Valve (Fig. 97) on the Compressor, allowing it to run idle. When the 
pressure drops to the minimum setting, the Pilot automatically closes the Intake 
Valve and Compressor resumes normal operation. Maximum and minimum pres- 
sures can be varied by resetting the Pressure Adjusting Screw (Fig. 96). 



133, How does a Pressure Switch operate? 

When maximum pressure in Air Receiver is reached, a Diaphragm is actuated 
breaking the circuit which automatically stops the motor. When pressure drops 
to minimum setting, the circuit is closed again, motor starts up and operates 
compressor until maximum pressure is reached. Switches with various cut-in 
and cut-out pressures are available for diflferent requirements. 

[ 28 ] 



134. What is the purpose of a Motor Starter? 

The Motor Starter, by means of resistance coils, reduces the starting current until 
the Motor comes up to normal speed, then gradually cuts out the resistance. 

135. How are Motors protected from overload? 

Small Motors are protected by fuses, and large ones by overload relays on the 
starting devices, or by fuses and circuit breakers at the line switch. 
Relays when used, are often provided with time-delay features so that circuits 
will not be opened by overloads of short duration that would not injure the Motor. 

136. What is a Centrifugal Pressure Re- 
lease? 

A feature incorporated in the com- 
pressor which protects the motor 
from overstrain when starting. It is 
supplied on outfits operated under 
conditions of frequent starting and 
stopping. It functions independently 
of the Pressure Switch, being oper- 
ated by the centrifugal action of a 
mechanism on the crankshaft. 



AT N0fih4AL SP££D BALLS 

uoye TO ouTs/oe ano 

VALVE CLOSFi Ai/f IS 

TH£N PUMPED INTO TANK 



137. How does the Centrifugal Pressure 
Release work? 

When the compressor starts up or 
slows down, shaft rotates slowly 
and balls (Fig. 98) move towards 
center forcing cam outward. This opens valve "Bleeding" 
air from the Compressor to Check Valve line allowing 
compressor to run idle. When normal speed is reached, 
balls move out by centrifugal force closing valve and air 
is pumped into air receiver. 



CENrRlFUCAL PRESSURE RELEASE 

STARTS UP 



SHAFT ROTATES SLOlVLV- 
BALLS MOVE TO CENTER- 



CAM /S THEN FORCEO 



WITH AIR BlEEDIHC 
COMPRESSOR RONS /OLE 
VMT/L NORMAL SPEED 

— ^ REACHED 
TUBE CONNECTS WITH 
BETWEEN COMPRESSO 
CHECK VALVC 




VALVE 

F/6 99 



C^ ^ 




EXHAUST 
VALVE 



138. What care should be given an Outfit? 

1. It should be filled with good grade auto cylinder oil, 
S.A.E. No. 10, for ordinary conditions: S.A.E. No. 20 
for temperatures above 100° F.; S.A.E. 10 that is fluid 
at sub-zero temperatures for outside use in winter. Oil should be changed after 
first month of operation, and then once every two or three months. 

2. It should be located where it will receive a supply of cool, clean, dry air. 

3. Air Strainer should be kept clean. Occasionally remove Air Strainer Felt, clean 
it, and replace. 

4. Air Receiver should be drained daily. 



139. How are Valves replaced? 

Remove Valve Caps and lift out Valve Assemblies, Disassemble and replace 
Valves. Note arrangement of Valve Parts (Fig. 99), 

140. What causes Compressor to knock? 

(a) Carbon on Piston (Fig. 100). 

(b) Loose or worn Wrist Pin. 

(c) Connecting Rod Bearing "frozen" due to lack of oil. 

(d) Worn Main Bearing. 

(e) Valve Assemblies improperly installed. 

[ 29] 



c*»»on on nsrof> 






etottec jn» sfsmem ~-~^ 



Of C0MPf9£SS0fi TROUBlCS 



/ 



fmoam" §es»in* • 



ntlgttf Attt 




111. Vlhmi rau^eik Compressor Co heal up? 

(h) N(j oil in crankcase (Fig 100). 

(b) Valve* sticking. 

(c) Insufficient air circulaUon due to outfit located too t Iom- lo wull. m toiilined 
space, etc. 

(d) Cylinder and Head coated with a thick deposit of paint. 

(e) VaJvr* dirtv or mvrrpd wjlli carbon 

(f) St 

(g) T. 

(h) BroKc-ii |^xri..lJ^^ \ nwtr 
(i) Air Strainer clogged up. 



142. Hlial rausr% C 



143 filial 



II tu op«-ialr lungrr pri iodn than nurmal? 

''' » . 
on cylinders. 

..IVM. 

rfikkor lo pump <*iP 



4t, V. 
Ill Vi-^r- \ 



E 10, lot 
it ft uar a 



Muid at liii 



(») 



INDEX 



Question 
No. 



Question 
No. 



Accessories. Spray Gun . . . 50-56 

Adapter 53 

Agitators 77-78 

Air Adjusting Valve .... 50 

Air Caps 20-23 

Air Caps, selecting .... 23 

Air Caps, types 21 

Air Compressors 129-131 

Air Condensers 103 

Air Conditioner — See Air Trans- 
formers 

Air Hose 85-87 

Air Leakage 40 

Air Motor Drive Agitator ... 78 

Air Pressure Unloader— See Auto- 
matic Unloader 
Air Purifier— See Air Trans- 
formers 
Air Reducing Valve — See Air 

Transformers 
Air Regulator— See Air Trans- 
formers 
Air Storage Chart .... 112 
Air Tool Requirements ... 121 
Air Transformers .... 92-102 

Air Valve 13 

Automatic Unloader .... 132 

B 

Ball and Cone 30 

Belt Drive Agitator .... 78 

"Bleeder" Gun 3 

Blow-By Valve — See Bleeder Gun 
Bottom Material Connection — See 
Fluid Inlet Extension 



Caps — See Air Caps 

Centrifugal Pressure Release . . 137 
Centrifugal Unloader— See Cen- 
trifugal Pressure Release" 
Cleaning. Air Caps .... 38 

Cleaning. Spray Guns ... 37 

Cocks — See Valves .... 56 

Compressing Outfits .... 104-128 
Compressing Outfits, Parts . . 128 

Compressing Outfits. Size . . , 119-120 
Compressor Troubles .... 140-143 

Compressors 129-131 

Compressors, Parts .... 131 
Connectors — See Couplings 
Containers, Material .... 57^1 
Couplers — See Couplings 

Couplings . 54 

Cups 59-68 



127 
123 
124 
43 
73 



125-126 

78 

113 



"Delivery", definition . 
Displacement 
Displacement Formula 
Distorted Spray Patterns 
Double Regulation 



Efficiency. Volumetric 

Electric Motor Drive Agitator . 

Engine Driven Outfits 

External Atomization — See External 

Mix Gun 
External Mix Gun . . . . 
Extractors— See Air Transformers 



Fluid Cut-OfI Valve .... 51 

Fluid Hose 84 & 88 

Fluid Inlet Extension .... 52 

Fluid Leakage 41 

Fluid Needle Adjustment ... 14 

Fluid Outlet Cocks— See Valves 

Fluid Tips 24-29 



Gravity Buckets 80-81 

Gravity Feed Cups .... 63-64 

Gravity Feed Gun .... 9 

Guns 1-48 



H 



Hose 

Hose Cleaner 

Hose Connections 

How Tor- 
Apply Hose Connections . 
Clean Air Caps . 
Clean Spray Guns . 
Disassemble Transformer 
Do Touch Up Job . 
Figure Displacement 
Hold Spray Gun 
Install Compressing Outfits 
Install Transformers 
Make Stroke 
Prepare Paint . 
Remove Spray Head 
Replace Valves - 
Select Compressor . 
Spray Corners . 



I 
Inner Containers — See Inserts 
Inner Tanks — See Inserts 
Inserts 



82-88 

37 

89-91 

91 
38 
37 

102 
49 

124 
32 

115 
96 
33 
31 
17 

139 

120 
34 



79 



[ 31 ] 



wmsm-^i^ 



Question 
No. 

Internal Atomization— See Internal 

Mix Gun 
Internal Mix Gun .... 6 

J 

Jerky. Fluttering Spray ... 42 

L 

Locking Bolt 15 

Lubrication, Spray Gun ... 36 

M 

Male Connectors — See Couplings 

Material Containers .... 57-81 

Material Cups 59-68 

Material Cut-OfiF Valves ... 51 
Material Hose — See Fluid Hose 

Material Tanks 69-77 

Mist 47 

Moisture in Air 98 

Moisture Trap — See Transformers 

Motor Starters 134 

Multiple Jet Cap 22 

N 

Nipples — See Couplings 

Non-Bleeder Gun ... 4 

Nozzle Sizes 25-27 

O 

Oil and Moisture Separator — See 

Transformers 
Oil Recommendations .... 144 

Oiling Gun 36 

"Orange Peel" 44 

Overload Protection .... 135 

Outlet Cocks— See Valves 

P 

Paint Strainer 55 

Paint Tanks 69-77 

Paint Pots— See Tanks 

Portable Outfits 114 

Pressure Cups 65-68 

Pressure Drop 87 

Pressure Feed Cups . 65-68 

Pressure Feed Tanks .... 69-77 
Pressure Reducing Valve — See 

Transformers 

Pressure Release I37 

Pressure Switch I33 

Pressure Switch Contr' 116 

Pressure Tanks 69-77 

Pumping Time 118 

R 

Removable Spray Head ... 16 

Refill Tanks— See Inserts 



Question 
No. 



Regulators — See Transformers 
Runs 



46 



Sags 46 

Separators — See Transformers 
Shut-Off Valves— See Cut-Off Valves 

Single Regulation Tanks . , . 72 
Single Stage Outfits .... 106-108 

•'Split" Spray 43 

Spray Guns 1-48 

Spray Head 16-19 

Spray Head Locking Bolt ... 15 

Spray Head Parts .... 19 

Spray Patterns 43 

Spray Width Adjustment ... 12 

Spraying Comers .... 34 

Spreader Adjustment Valve . 12 

"Starving" Gun 48 

Stationary Outfits .... 114-115 

Strainers, Material .... 55 

Streaks 45 

Stroke 33 

Suction Feed Cups .... 61-62 

Suction Feed Gun .... 7 
Suction Valve Unloader— See Un- 

loader 
Syphon Cups— See Suction Feed 

Cups 
Syphon Feed— See Suction Feed 



Tanks 69-77 

Tips— See Fluid Tip 

Top Feed— See Gravity Feed 

Touch -Up Procedure .... 49 

Transformer Parts .... 94 

Transformer Troubles . 98-101 

Transformers 92-102 

Trap, Moisture — See Transformers 

Troubles, Compressor .... 140-143 

Troubles. Spray Gun .... 39-48 

Troubles. Transformers . 98-101 

Two Stage Outfits .... 109-111 
Two Stage vs. Single Stage 



U 



Unloader, Automatic 
Unloader Control 



Valves, Air and Fluid 
Valves, Replacement of . 

W 

Water and Moisture Trap— See 
Transformers 



132 
116 



56 
139 



[ 32 ] 



I